Plate-Type Heat Exchanger And Air-Conditioning Circuit For A Vehicle

ABSTRACT

A plate-type heat exchanger ( 30 ) for a vehicle cools a cooling fluid by means of a coolant. The exchanger ( 30 ) has a plurality of heat exchanger plates ( 40 ) which are stacked one on top of the other. Coolant chambers ( 44 ) and cooling fluid chambers ( 46 ), which each have an inflow ( 48, 52 ) and an outflow ( 50, 54 ) for the coolant and/or the cooling fluid are formed between adjacent heat exchanger plates ( 40 ). The coolant and/or cooling fluid chambers ( 44, 46 ) are embodied in their entirety as U-shaped flow ducts ( 64, 68 ), wherein the assigned inflow ( 48, 52 ) is arranged at the end of a first limb, and the assigned outflow( 50, 54 ) is arranged at the end of a second limb, of the flow ducts ( 64, 68 ). The invention also relates to an air-conditioning circuit ( 10 ) for a vehicle.

The invention relates to a plate-type heat exchanger for a vehicle forcooling a cooling fluid by means of a coolant, having a plurality ofheat exchanger plates which are stacked one on top of the other, and anair-conditioning circuit for a vehicle, in particular for a vehiclehaving an electric motor.

Plate-type heat exchangers of the type specified at the beginning areknown in which the cooling fluid or the coolant flows through theintermediate spaces between adjacent plates, wherein the cooling fluidflows from a first side of the plate-type heat exchanger to the oppositesecond side of the plate-type heat exchanger, while the coolant flows inthe opposite direction from the second end to the first end of theplate-type heat exchanger. The length of the flow ducts in theplate-type heat exchanger corresponds here essentially to the length ofthe plate-type heat exchanger from the first end to the second end. Theouter dimensions of the plate-type heat exchanger and the position ofthe connections of the plate-type heat exchanger are therefore dependenton the desired length of the flow ducts in the plate-type heatexchanger.

The object of the invention is to provide a plate-type heat exchangerwith a compact design as well as an air-conditioning circuit for avehicle, which air-conditioning circuit can be embodied in a compactfashion which is optimized for the installation space.

The object of the invention is achieved by means of a plate-type heatexchanger for a vehicle for cooling a cooling fluid by means of acoolant, having a plurality of heat exchanger plates which are stackedone on top of the other, wherein coolant chambers and cooling fluidchambers, which each have an inflow and an outflow for the coolantand/or the cooling fluid, are formed between adjacent heat exchangerplates. The coolant and/or cooling fluid chambers are embodied in theirentirety as U-shaped flow ducts, wherein the assigned inflow is arrangedat the end of the first limb, and the assigned outflow is arranged atthe end of the second limb, of the U-shaped flow duct. The U-shaped flowducts make it possible to double the length of the flow duct of thecoolant chambers and/or cooling fluid chambers without increasing thelength of the plate-type heat exchanger, and to position the connectionsfor the inflow and outflow of the coolant and/or of the cooling fluid ina flexible way.

The heat exchanger plates preferably have, in the plane of their plates,both a main extent direction and a secondary extent direction runningperpendicular thereto, and are arranged one next to the other in astacking direction which runs perpendicular to the main extent directionand to the secondary extent direction (referred to below as “definitionof direction”).

With this predefined definition of direction it is advantageous that theinflow and outflow for the coolant are provided in the main extentdirection, at the same end of the heat exchanger plates. In this way,the inflow and outflow for the coolant can be positioned near to oneanother without having to shorten the length of the flow duct for thecoolant.

The heat exchanger plates can be substantially rectangular and the mainextent direction can then run in the longitudinal direction of theplates.

A common inflow connection and outflow connection for all the coolantchambers is provided with a connection component which permits directattachment of an expansion valve for the coolant to the plate-type heatexchanger. In this way it is possible to eliminate the need for a linesystem between the expansion valve and the plate-type heat exchanger.

In order to achieve a uniform cooling performance in all of the coolantchambers, the connection component can have a coolant distributor whichhomogenizes distribution of the coolant phase mixture among the variouscoolant chambers of the plate-type heat exchanger.

In the above-mentioned definition of direction, the inflow and outflowfor the cooling fluid are provided at the same or at opposite ends ofthe heat exchanger plates in the main extent direction. This permits avariable arrangement of the connections for the cooling fluid.

For a flexible arrangement of the connections of the plate-type heatexchanger on a primary circuit and secondary circuit, in each case acommon inflow connection and a common outflow connection can be providedfor all the coolant chambers and in each case a common inflow connectionand a common outflow connection can be provided for all the coolingfluid chambers, wherein the common inflow connection and outflowconnection for the coolant are arranged in the stacking direction on thesame lateral surface or on opposite lateral surfaces of the plate-typeheat exchanger, as are the inflow connection and outflow connection forthe cooling fluid.

An end plate can be provided on a common inflow connection and/oroutflow connection for all the cooling fluid chambers, which end plateis arranged in front or behind the heat exchanger plates in the stackingdirection and forms at least one flow duct for the cooling fluid, whichflow duct connects the common inflow connection and/or outflowconnection of the heat exchanger plates to a connection for a coolingfluid system. In this way, the end plate of the plate-type heatexchanger forms a type of adaptor which permits a compact andadvantageously arranged connection to the cooling fluid system.

In the above-mentioned definition of direction, a further embodimentprovides for the inflow and outflow for the coolant to be arranged inthe main extent direction, at opposite ends of the heat exchangerplates, in the same way as the inflow and outflow for the cooling fluid.Given a corresponding orientation of the plate-type heat exchanger, thisarrangement of the connections permits a connection for cooling fluid atthe upper end of the heat exchanger plates and a connection for coolantat the lower end of the heat exchanger plates. This therefore easilypermits, on the one hand, degassing of the cooling fluid chambers and,on the other hand, a return flow of oil in the coolant chambers.

The directions of flow in adjoining coolant chambers and cooling fluidchambers can be the same or opposite. The transmission of heat betweenthe coolant and the cooling fluid along the flow duct can be optimizedby the selection of the direction of flow of the coolant and coolingfluid.

According to a further embodiment, the heat exchanger plates can form aflow duct in the cooling fluid chambers, which flow ducts runs from aninflow of the cooling fluid at one end of the heat exchanger plates inthe main extent direction to an outflow of the cooling fluid at theopposite end of the heat exchanger plates.

In order to improve the overall effectiveness of the exchange of heatbetween the cooling fluid and the coolant, the difference in pressureacross the first limb of the U-shaped flow duct for the coolant isbetween 70% and 100%, preferably between 80% and 92% of the overalldifference in pressure, and the difference in pressure across the secondlimb of the U-shaped flow duct for the coolant in the direction of flowis between 0% and 30%, preferably between 8% and 20% of the overalldifference in pressure.

The U shape of the flow ducts is preferably formed by an intermediatewall which is provided by a part, which connects the adjacent heatexchanger plates, or by a shaped section of at least one heat exchangerplate. This permits a simple design of the plate-type heat exchanger.

In order to homogenize the distribution of the coolant or the coolingfluid in the U-shaped flow ducts, the limbs of the U-shaped flow ductscan be formed by numerous elongated ducts arranged one next to theother.

The invention also relates to an air-conditioning circuit for a vehicle,in particular for a vehicle having an electric motor, with a primarycircuit for a coolant and a secondary circuit for a cooling fluid,wherein the primary circuit and the secondary circuit are coupled to theplate-type heat exchanger according to the invention. Since theplate-type heat exchanger itself is of compact design and has a flexiblearrangement of the connections for the coolant and cooling fluid, acompact design which can be implemented in a flexible way is madepossible for the air-conditioning circuit.

Further features and advantages of the invention can be found in thefollowing description and in the following drawings, to which referenceis made. In the drawings:

FIG. 1 shows a schematic view of an air-conditioning circuit accordingto the invention with a primary circuit for a coolant and a secondarycircuit for a cooling fluid;

FIG. 2 shows a sectional view of a plate-type heat exchanger accordingto the invention along the sectional line II-II in FIG. 3;

FIG. 3 shows a plan view of the plate-type heat exchanger according toFIG. 2 in a stacking direction;

FIG. 4 shows a schematic view of the plate-type heat exchanger accordingto FIG. 2 with connections for the coolant and cooling fluid which arearranged on the same lateral surface of the plate-type heat exchanger;

FIG. 5 shows a schematic view of the plate-type heat exchanger accordingto FIG. 2 having connections for coolant and cooling fluid which arearranged on opposite lateral surfaces of the plate-type heat exchanger;

FIG. 6 shows a direction of flow diagram with associated temperatureprofile diagram according to a first embodiment of the invention;

FIG. 7 shows a direction of flow diagram with associated temperatureprofile diagram according to a second embodiment of the invention;

FIG. 8 shows a direction of flow diagram with associated temperatureprofile diagram according to a third embodiment of the invention;

FIG. 9 shows a direction of flow diagram with associated temperatureprofile diagram according to a fourth embodiment of the invention;

FIG. 10 shows a plate-type heat exchanger according to FIG. 9 with afirst arrangement of the connections for the cooling fluid;

FIG. 11 shows a plate-type heat exchanger according to FIG. 9 with asecond alternative arrangement of the connections for the cooling fluid;

FIG. 12 shows a plate-type heat exchanger according to FIG. 9 with athird alternative arrangement of the connections for the cooling fluid;

FIG. 13 shows a schematic view of four heat exchanger plates of aplate-type heat exchanger according to the invention;

FIG. 14 shows an alternative embodiment of four heat exchanger plates ofa plate-type heat exchanger according to the invention;

FIG. 15 shows a view of a detail of the plate-type heat exchangeraccording to FIG. 2 with a coolant distributor; and

FIGS. 16 a, 16 b and 16 c show schematic views of various embodiments ofa coolant distributor according to FIG. 15.

FIG. 1 shows a schematic drawing of an air-conditioning circuit 10 for avehicle with a primary circuit 12 for a coolant and a secondary circuit14 for a cooling fluid.

The vehicle is, for example, a vehicle having an electric motor, inparticular a hybrid vehicle or a pure electric vehicle, with a batterywhich is to be cooled by the air-conditioning circuit.

In the primary circuit 12, a compressor 16, a condenser 18 and a drier20 are provided. The primary circuit 12 is divided into two secondaryregions, which can each be closed or opened by a valve 22.

In the first secondary region of the primary circuit 12, an expansionvalve 24 and vaporizer 26 are provided. The vaporizer 26 is part of avehicle air-conditioning system for the passenger compartment of avehicle.

An expansion valve 28 and a plate-type heat exchanger 30 are provided inthe second secondary region of the primary circuit 12. The plate-typeheat exchanger 30 is, furthermore, integrated into the secondary circuit14 and permits a cooling fluid in the secondary circuit 14 to be cooledby the coolant in the primary circuit 12.

The secondary circuit 14 has a pump 32 which pumps the cooling fluidthrough the secondary circuit 14. The secondary circuit 14 alsocomprises a storage device 34 for the cooling fluid. A first coolingdevice 36 for a battery and a second cooling device 38 for an electroniccomponent are arranged at various positions in the secondary circuit 14.The position of the cooling devices 36, 38 in the secondary circuit 14can depend, in particular, on the required cooling performance.

FIG. 2 shows a sectional view through the plate-type heat exchanger 30.A plurality of heat exchanger plates 40 are stacked one on top of theother in a stacking direction 42, wherein coolant chambers 44 andcooling fluid chambers 46, which each have an inflow 48, 52 and anoutflow 50, 54 for the coolant and/or the cooling fluid, are formedalternately between adjacent heat exchanger plates 40.

On the right-hand side in FIG. 2, an end plate 56 is provided which isarranged behind the heat exchanger plates 40 in the stacking direction.In the embodiment shown, the end plate 56 serves, for example, to attachthe plate-type heat exchanger 30. The end plate 56 can also be part of ahousing of the plate-type heat exchanger 30.

The heat exchanger plates 40 have, in the plane of their plates, both amain extent direction 58 and a secondary extent direction 60 runningperpendicular thereto, said main extent direction 58 and secondaryextent direction 60 each running perpendicular to the stacking direction42. In FIG. 2, the secondary extent direction 60 runs perpendicular tothe plane of the drawing.

The various inflows 48 of the various coolant chambers 44 lie in astraight line and therefore form a common inflow connection 49 for allthe coolant chambers 44. At the common inflow connection 49, aconnection component 62 is provided which permits direct attachment tothe expansion valve 28 to the plate-type heat exchanger 30. Suchexpansion valves 28 have a small lateral distance between the inflowduct and the outflow duct. In the embodiments according to theinvention, these ducts are coaxial to the inflows 48 and outflows 50.

In a way which is analogous to the inflows 48 of the coolant, theinflows 52 of the cooling fluid of the various cooling fluid chambers 46also lie along a straight line and form a common inflow connection 53for all the cooling fluid chambers. On the left-hand side of theplate-type heat exchanger 30, a pipe of the secondary circuit 14 isconnected to the common inflow connection 53 of the cooling fluidchambers 46.

In a way which is analogous to the inflow connections 49, 53, all theoutflows 50, 54 for the coolant and/or the cooling fluid are embodied ascommon outflow connections 51, 55.

FIG. 3 shows a plan view of the plate-type heat exchanger 30 in thestacking direction 42. The heat exchanger plates 40 are substantiallyelongate and rectangular, and the main extent direction 58 is in thelongitudinal direction of the heat exchanger plates 40. Shown in thelower region of the plate-type heat exchanger 30 is the connectioncomponent 62 with the common inflow connection 49 of all the coolantchambers 44, and with the common outflow connection 51 of all thecoolant chambers 44.

The distance between the inflow 48 and outflow 50 of the coolant of thecoolant chambers 44 is small compared to the extent of the heatexchanger plates 40 in the main extent direction 58. As is shown in thefollowing figures, this small distance permits the expansion valve 28 tobe mounted directly on the plate-type heat exchanger 30 without pipes orlines for the coolant being required between the expansion valve 28 andthe plate-type heat exchanger 30.

The common inflow connection 53 and the common outflow connection 55 ofall the cooling fluid chambers 46 of the plate-type heat exchanger 30are in turn arranged with small spacing in the upper region of theplate-type heat exchanger 30.

FIG. 4 shows a schematic view of the plate-type heat exchanger 30 in aplan view in the direction of the secondary extent direction 60. As canbe clearly seen in this perspective, the common inflow connection 49 andthe common outflow connection 51 for all the coolant chambers 44, andthe common inflow connection 53 and the common outflow connection 55 forall the coolant chambers 46, are arranged on the same lateral surface ofthe plate-type heat exchanger 30 with respect to the stacking direction42.

FIG. 5 shows an alternative arrangement of the inflow connection 53 andof the outflow connection 55 of the cooling fluid chambers 46 on theopposite side surface of the plate-type heat exchanger 30 with respectto the stacking direction 42. The inflow connection 49 and the outflowconnection 51 of the cooling fluid chambers 44 have the commonconnection component 62, on which the expansion valve 28 is directlyprovided.

In each case a pipeline element of the secondary circuit 14 is connectedto the inflow connection 53 and to the outflow connection 55 of thecooling fluid chambers 46.

FIG. 6 shows the flow profile of the coolant in the coolant chambers 44and the profile of the cooling fluid in the cooling fluid chambers 46 ofa first embodiment of the plate-type heat exchanger 30, and thetemperature profile of the coolant and of the cooling fluid.

The coolant passes via the inflow 48 into the coolant chamber 44 whichis formed by two adjacent heat exchanger plates 40. The coolant chamber44 is in its entirety a U-shaped flow duct 64, wherein the inflow 48 ofthe coolant is arranged at the end of the first limb, and the outflow 50is arranged at the end of the second limb, of the U-shaped flow duct 64.The two limbs of the U-shaped flow duct 64 are separated by anintermediate wall 66.

The “U” extends over approximately the entire length of the heatexchanger plates 40.

The cooling fluid chamber 46 is embodied as a U-shaped flow channel 68for the cooling fluid, in the same way by an intermediate wall 66. Theinflow 52 of the cooling fluid chamber 46 is arranged at the end of thefirst limb, and the outflow 54 is arranged at the end of the secondlimb, of the U-shaped flow duct 68 in the cooling fluid chamber 46. TheU shape of the flow duct 68 for the cooling fluid is therefore invertedcompared to the U-shaped flow duct 64 of the coolant, wherein the limbsof the two flow ducts 64, 68 rest one on the other.

In the embodiment according to FIG. 6, the directions of flow of thecoolant and cooling fluid in adjoining coolant chambers 44 and coolingfluid chambers 46 in the two limbs are respectively opposed to oneanother.

FIG. 6 also shows the temperature profile in the first limb A fromposition A₁ to A₂, and in the second limb B from the position B₁ to B₂in both chambers 44, 46. Given an inflow temperature of the coolingfluid at A₂ of 10° C. and an outflow temperature of the cooling fluid atB₁ of 4° C. as well as an inflow temperature of the coolant at A₁ of 4°C. and an outflow temperature of the coolant at B₂ of 1° C., aneffective difference in temperature Δtlog of 5.1 K occurs in the limb A,an effective difference in temperature Δtlog of 3.6 K occurs in the limbB, and overall an average difference in the temperature Δtlog of 4.4 Krespectively occurs between adjacent chambers 44, 46. The higher thedifference in temperature between the coolant and the cooling fluid, thebetter the exchange of heat between the two.

FIG. 7 shows a second embodiment of the plate-type heat exchanger 30,wherein the design is essentially identical to the first embodiment. Thesecond embodiment differs from the first in that the direction of flowin the coolant chamber 44 has been inverted. In the coolant chamber 44,the inflow 48 is therefore interchanged with the outflow 50 compared tothe first embodiment.

The direction of flow in adjoining coolant chambers 44 and cooling fluidchambers 46 is therefore the same.

The coolant now firstly flows through the limb B of the U-shaped flowduct 64 from B₁ to B₂ and in the process cools from 4° C. to 2° C. Thecoolant subsequently flows through the limb A from A₁ to A₂, wherein itcools from 2° C. to 1° C. The saturation temperature is 0° C. As isapparent from the temperature profile diagrams, the difference intemperature in the limb A is greater than in the preceding embodiment,wherein the effective difference in temperature at Δtlog is 7 K. In thelimb B, the difference in temperature is, in contrast, somewhat smallerand is 2.5 K at Δtlog. The average effective difference in temperatureacross the entire flow duct is 4.7 K at Δtlog. By making the directionsof flow the same in adjoining coolant chambers 44 and cooling fluidchambers 46, an improved difference in temperature can be surprisinglyachieved with the U-shaped flow ducts, as a result of which theeffectiveness of the plate-type heat exchanger 30 is increased.

FIG. 8 shows a third embodiment of the plate-type heat exchanger 30. Thedirection of flow in the U-shaped flow ducts 64, 68 of the coolantchambers 44 and/or of the cooling fluid chambers 46 is identical to thesecond embodiment. The third embodiment differs from the secondembodiment only in that the difference in pressure across the limb B ofthe U-shaped flow duct 64 for the coolant is between 70% and 100%,preferably between 80% and 92% of the overall difference in pressure,while the difference in pressure across the limb A is between 0% and30%, preferably between 8% and 20% of the overall difference inpressure. In the limb B, the first limb in the direction of flow of thecoolant, the coolant cools to a large degree and reaches 0.5° C. in theexample shown. The cooling results from the static pressure which dropsowing to the pressure loss, and owing to the resulting lowering of thecoolant saturation temperature.

In contrast, no further cooling of the coolant takes place in the limb Asince the saturation temperature only now drops at minimum byapproximately 0.5 K due to the small pressure loss in the limb A.However, this drop in temperature has a superimposed coolant overheatingof 1 K, with the result that the temperature at the coolant outlet A₂ ofthe limb A is even 0.5 K higher than at the inlet A₁. In this way, avery large difference in temperature is possible between the coolantchamber 44 and the cooling fluid chamber 46 in the region of limb A,wherein the effective difference in temperature at Δtlog is 7.6 K. Inthe limb B, the effective difference in temperature at Δtlog is 3.2 K.The average effective difference in temperature between the two limbs is5.4 K at Δtlog, as a result of which a further improvement was achievedin the effectiveness of the plate-type heat exchanger 30.

The differences in pressure in the two limbs of the U-shaped flow duct64 for the coolant can be achieved in various ways. In the exampleshown, the difference in pressure is achieved by a different flowresistance in the two limbs of the flow duct 64. For this purpose,different fin arrangements of the flow ducts or various inserts in theflow ducts are provided. Alternatively, the two limbs can also beembodied with a different flow cross section, by virtue of the factthat, for example, the intermediate wall 66 does not divide the twolimbs of the U-shaped flow duct 64 uniformly.

FIG. 9 shows a fourth embodiment of the plate-type heat exchanger 30,wherein only the flow duct 64 for the coolant in the coolant chambers 44is embodied in a U shape. The position of expansion valve 28 in thecoolant chamber 44 is shown by dotted lines. The embodiment of thecoolant chambers 44 and the direction of flow of the coolant through theU-shaped flow duct 64 is identical to the third embodiment of theplate-type heat exchanger 30. The fourth embodiment differs from thepreceding embodiments in that the cooling fluid chambers 46 have a flowduct 70 which runs from the inflow 52 of the cooling fluid at the oneend of the heat exchanger plates 40, parallel to the main extentdirection 58 to an outflow 54 of the cooling fluid at the opposite endof the heat exchanger plates 40.

The difference in temperature diagrams at the top and bottom in FIG. 9relate to the regions of the limbs A and B of the coolant chambers 44.The regions A and B are part of the same flow duct 70 through whichthere is a flow in one direction in the adjacent cooling fluid chambers46. The temperature profile of the cooling fluid is therefore the samein both regions.

The temperature profile of the coolant corresponds to the temperatureprofile of the coolant in the third embodiment of the plate-type heatexchanger 30.

The effective difference in temperature in the limb A is 5.64 K atΔtlog, and the effective difference in temperature in the region of thelimb B is 4.63 K at Δtlog.

In the embodiment shown in FIG. 9, the flow duct 70 of the cooling fluidchambers 46 does not need an intermediate wall 66. All that is thereforenecessary is to provide an intermediate wall 66 in the coolant chambers44. An intermediate wall 66 is therefore necessary only in every secondchamber in the plate-type heat exchanger 30, which simplifies the designof the plate-type heat exchanger 30.

Various connection variants for connecting the plate-type heat exchanger30 to the secondary circuit 14 are provided in the FIGS. 10, 11 and 12.

FIG. 10 shows a perspective view of the plate-type heat exchanger 30,wherein the expansion valve 28 is provided at the bottom on theleft-hand side of the plate-type heat exchanger 30. Owing to the spacerequirement of the expansion valve 28, the outflow connection 55 for thecooling fluid is possible at the same end in the main extent direction58 of the plate-type heat exchanger 30 only on the lateral surface,lying opposite the expansion valve 28, in the stacking direction 42. Theinflow connection 53 which lies at the top in the main extent direction58 can lie on the same lateral surface in the stacking direction 42 asthe outflow connection 55, as is shown by a dotted line in FIG. 10, onthe opposite lateral surface with respect to the stacking direction 42.

In the plate-type heat exchanger 30 which is shown in FIG. 11, anadditional end plate 56 is provided on the lateral surface, lyingopposite the expansion valve 28, of the plate-type heat exchanger 30 inthe stacking direction 42. The end plate 56 forms a flow duct, indicatedby the dotted line, for the cooling fluid, which flow duct connects thecommon outflow connection 55 of the heat exchanger plates 40 to aconnection 72 for the cooling fluid system of the secondary circuit 12.In this way it is possible for the line systems of the secondary circuit14 to each be provided at the same end in the main extent direction 58of the plate-type heat exchanger 30, even though the common inflow andoutflow connections 53, 55 of the cooling fluid chambers 46 lie atopposite ends of the plate-type heat exchanger 30 in the main extentdirection 58.

FIG. 12 shows a similar embodiment, wherein the cooling fluidconnections of the secondary circuit 14 lie on opposite sides ofsurfaces of the plate-type heat exchanger 30 in the stacking direction42.

FIG. 13 in turn represents an embodiment of the plate-type heatexchanger 30, wherein the heat exchanger plates 40 are each of planardesign and are spaced apart by wall elements 74 in order to form thecoolant chambers 44 and the cooling fluid chambers 46. Further wallelements form the intermediate wall 66, which connects the adjacent heatexchanger plates 40.

FIG. 14 shows a further embodiment of the plate-type heat exchanger 30,wherein in each case two adjacent heat exchanger plates 40 have a shapedsection 76, which shaped sections together form the intermediate wall 66of the cooling fluid chambers 46. The intermediate wall 66 of thecoolant chambers 44 is, in contrast, formed, in a way which is analogousto FIG. 13, by a wall element which connects the adjacent heat exchangerplates 40 to one another.

Inserts 78, which divide the coolant chambers 44 or cooling fluidchambers 46 into small parallel ducts which run along the limbs A and Bin FIGS. 6 to 9, are provided in the coolant chambers 44 and the coolingfluid chambers 46 in FIGS. 13 and 14.

FIG. 15 shows a view of a detail of the plate-type heat exchanger 30according to FIG. 2, wherein a throttle direction 80 is provided in theregion of the connection component 62. In the embodiment shown in FIG.15, the throttle device 80 is a pipe with calibrated diameter whichprojects from the connecting flange at least partially into one or morecoolant chambers 44. A filter 82 is provided in front of the throttledevice 80.

FIG. 16 a illustrates an embodiment of a coolant distributor 81 of asimple design, wherein an opening which is relatively large compared tothe throttle device 80 is provided at the common inflow connection 49 ofthe coolant chambers 44, which opening causes only part of the overalldifference in pressure between the high pressure and low pressure; therest of the difference in pressure is compensated by the expansion valve28.

FIG. 16 b shows an embodiment of the coolant distributor with a pipewith a calibrated diameter which extends into the common inflowconnection 49 of the coolant chambers 44.

When the coolant exits the reduced opening 81 or the pipe with acalibrated diameter, the mixture of coolant phase is swirled, whereinhomogenization of the mixture takes place and a more uniformdistribution among the various coolant chambers 44 is made possible. Inthis way, a uniform cooling performance in all the coolant chambers 44is achieved.

FIG. 16 c shows a coolant distributor 81 in the form of a distributorinsert which permits homogenous distribution of the coolant phasemixture among the various coolant chambers 44 of the plate-type heatexchanger 30.

1. A plate-type heat exchanger (30) for a vehicle for cooling a coolingfluid by means of a coolant, the heat exchanger (30) having a pluralityof heat exchanger plates (40) which are stacked one on top of eachother, wherein coolant chambers (44) and cooling fluid chambers (46),which each have an inflow (48, 52) and an outflow (50, 54) for thecoolant and/or the cooling fluid, are formed between adjacent heatexchanger plates (40), and the coolant and/or cooling fluid chambers(44, 46) are embodied altogether as U-shaped flow ducts (64, 68),wherein the assigned inflow (48, 52) is arranged at the end of a firstlimb, and the assigned outflow (50, 54) is arranged at the end of asecond limb, of the U-shaped flow duct.
 2. A plate-type heat exchanger(30) according to claim 1, wherein the heat-exchanger plates (40) have,in the plane of their plates, both a main extent direction (58) and asecondary extent direction (60) running perpendicular thereto, and arearranged one next to the other in a stacking direction (42) which runsperpendicular to the main extent direction (58) and to the secondaryextent direction (60), and wherein the inflow (48) and outflow (50) forthe coolant are provided in the main extent direction (58), at the sameend of the heat exchanger plates (40).
 3. A plate-type heat exchanger(30) according to claim 2, comprising a common inflow connection (49)and outflow connection (51) for all the coolant chambers (44), wherein aconnection component (62) is provided which permits direct attachment ofan expansion valve (28) for the coolant to the plate-type heat exchanger(30).
 4. A plate-type heat exchanger (30) according to claim 3, whereinthe connection component (62) has a coolant distributor (81) whichhomogenizes distribution of the coolant phase mixture among differentcoolant chambers (44) of the plate-type heat exchanger (30).
 5. Aplate-type heat exchanger (30) according to claim 1, wherein the heatexchanger plates (40) have, in the plane of their plates, both a mainextent direction (58) and a secondary extent direction (60) runningperpendicular thereto, and are arranged one next to the other in astacking direction (42) which runs perpendicular to the main extentdirection (58) and to the secondary extent direction (60), and whereinthe inflow (52) and outflow (52) (54) for the cooling fluid are providedin the main extent direction (58), at the same end or at opposite endsof the heat exchanger plates (40).
 6. A plate-type heat exchanger (30)according to claim 1, comprising in each case a one common inflowconnection (49) and a common outflow connection (51) for all the coolantchambers (44), and in each case a common inflow connection (53) and acommon outflow connection (55) for all the cooling fluid chambers (46),wherein the common inflow connection (49) and outflow connection (51)for the coolant are arranged in the stacking direction (42) on the samelateral surface or on opposite lateral surfaces of the plate-type heatexchanger (30), as are the inflow connection (53) and outflow connection(55) for the cooling fluid.
 7. A plate-type heat exchanger (30)according to claim 1, comprising a common inflow connection (53) and/oroutflow connection (55) for all the cooling fluid chambers (46), whereinan end plate (56) is provided which is arranged in front of or behindthe heat exchanger plates (40) in the stacking direction (42) and whichforms at least one flow duct for the cooling fluid, the at least oneflow duct connects the common inflow connection (53) and/or outflowconnection (55) of the heat exchanger plates (40) to a connection (72)for a cooling fluid system.
 8. A plate-type heat exchanger (30)according to claim 1, wherein the heat exchanger plates (40) have, inthe plane of their plates, both a main extent direction (58) and asecondary extent direction (60) running perpendicular thereto, and arearranged one next to the other in a stacking direction (42) which runsperpendicular to the main extent direction (58) and to the secondaryextent direction (60), and in that the inflow (48) and outflow (50) forthe coolant are arranged in the main extent direction (58), at oppositeends of the heat exchanger plates (40), as are the inflow (52) andoutflow (54) for the cooling fluid.
 9. A plate-type heat exchanger (30)according to claim 8, wherein the directions of flow in adjoiningcoolant chambers (44) and cooling fluid chambers (46) are the same oropposed.
 10. A plate-type heat exchanger (30) according to claim 1,wherein the heat exchanger plates (40) form a flow duct (70) in thecooling fluid chambers (46), and the flow duct (70) runs from an inflow(52) of the cooling fluid at one end of the heat exchanger plates (40)in the main extent direction (58) to an outflow (54) of the coolingfluid at the opposite end of the heat exchanger plates (40).
 11. Aplate-type heat exchanger (30) according to claim 1, wherein thedifference of pressure across the first limb of the U-shaped flow duct(64) for the coolant is between 70% and 100% of the overall differenceof pressure, and the difference of pressure across the second limb ofthe U-shaped flow duct (64) for the coolant in the direction of flow isbetween 0% and 30% of the overall difference of pressure.
 12. Aplate-type heat exchanger (30) according to claim 1, wherein the U-shapeof the flow ducts (64, 68) is formed by an intermediate wall (66) whichis formed by a part (74), which connects the adjacent heat exchangerplates (40), or by a shaped section (76) of at least one heat exchangerplate (40).
 13. A plate-type heat exchanger (30) according to claim 1,wherein the limbs of the U-shaped flow ducts (64, 68) are formed bynumerous elongated ducts arranged one next to the other.
 14. Anair-conditioning circuit (10) for a vehicle, the air-conditioningcircuit (10) having a primary circuit (12) for a coolant and a secondarycircuit (14) for a cooling fluid, wherein the primary circuit (12) andthe secondary circuit (14) are coupled via the plate-type heat exchanger(30) according to claim 1.